From: Anton Blanchard <anton@samba.org>
To: linux-kernel@vger.kernel.org
Subject: kmap() while holding spinlock
Date: Thu, 26 Jul 2001 16:12:19 -0400 [thread overview]
Message-ID: <20010726161219.D4963@krispykreme> (raw)
Hi,
I was debugging a lockup on sparc32 where we took a page_table_lock
in handle_mm_fault and then tried to take the same one again in
swap_out_mm. So it looks like we are scheduling somewhere inside
handle_mm_fault while holding the page_table_lock.
This machine might have highmem (Im awaiting more information). If
so copy_user_highpage and clear_user_highpage could sleep if we
run out of kmap entries. There are two problems:
do_anonymous_page calls clear_user_highpage with the page_table_lock held.
do_wp_page calls break_cow with the page_table_lock held.
Since I dont think we can drop the lock, do we need a kmap_atomic for
these?
Anton
next reply other threads:[~2001-07-26 6:17 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2001-07-26 20:12 Anton Blanchard [this message]
2001-07-26 12:17 ` kmap() while holding spinlock Ingo Molnar
2001-07-26 12:29 ` highmem-2.4.7-A0 [Re: kmap() while holding spinlock] Ingo Molnar
2001-07-26 18:25 ` Jeremy Linton
2001-07-26 19:50 ` Hugh Dickins
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